Fit-for-Purpose Ki-67 Immunohistochemistry Assays for Breast Cancer.

New therapies are being developed for breast cancer, and in this process, some "old" biomarkers are reutilized and given a new purpose. It is not always recognized that by changing a biomarker's intended use, a new biomarker assay is created. The Ki-67 biomarker is typically assessed by immunohistochemistry (IHC) to provide a proliferative index in breast cancer. Canadian laboratories assessed the analytical performance and diagnostic accuracy of their Ki-67 IHC laboratory-developed tests (LDTs) of relevance for the LDTs' clinical utility. Canadian clinical IHC laboratories enrolled in the Canadian Biomarker Quality Assurance Pilot Run for Ki-67 in breast cancer by invitation. The Dako Ki-67 IHC pharmDx assay was employed as a study reference assay. The Dako central laboratory was the reference laboratory. Participants received unstained slides of breast cancer tissue microarrays with 32 cases and performed their in-house Ki-67 assays. The results were assessed using QuPath, an open-source software application for bioimage analysis. Positive percent agreement (PPA, sensitivity) and negative percent agreement (NPA, specificity) were calculated against the Dako Ki-67 IHC pharmDx assay for 5%, 10%, 20%, and 30% cutoffs. Overall, PPA and NPA varied depending on the selected cutoff; participants were more successful with 5% and 10%, than with 20% and 30% cutoffs. Only 4 of 16 laboratories had robust IHC protocols with acceptable PPA for all cutoffs. The lowest PPA for the 5% cutoff was 85%, for 10% was 63%, for 20% was 14%, and for 30% was 13%. The lowest NPA for the 5% cutoff was 50%, for 10% was 33%, for 20% was 50%, and for 30% was 57%. Despite many years of international efforts to standardize IHC testing for Ki-67 in breast cancer, our results indicate that Canadian clinical LDTs have a wide analytical sensitivity range and poor agreement for 20% and 30% cutoffs. The poor agreement was not due to the readout but rather due to IHC protocol conditions. International Ki-67 in Breast Cancer Working Group (IKWG) recommendations related to Ki-67 IHC standardization cannot take full effect without reliable fit-for-purpose reference materials that are required for the initial assay calibration, assay performance monitoring, and proficiency testing.

Neoadjuvant Chemotherapy in Breast Cancer: Review of the Evidence and Conditions That Facilitated Its Use during the Global Pandemic.

Practice and behaviour change in healthcare is complex, and requires a set of critical steps that would be needed to implement and sustain the change. Neoadjuvant chemotherapy for breast cancer is traditionally used for locally advanced disease and is primarily advantageous for surgical downstaging purposes. However, it does also offer patients with certain biologic subtypes such as the triple negative or Her2 positive breast cancers the opportunity to improve survival, even in early stage disease. During the height of the pandemic, an opportunity and motivation for the increased use of neoadjuvant therapy in breast cancer was identified. This paper describes the conditions that have supported this practice change at the provider and institutional levels. We also include our own institutional algorithm based on tumor biology and extent of disease that have guided our decisions on breast cancer management during the pandemic. Our processes can be adapted by other institutions and breast oncology practices in accordance with local conditions and resources, during and beyond the pandemic.

Selecting Patients for Oncotype DX Testing Using Standard Clinicopathologic Information.

INTRODUCTION: Indiscriminate ordering of Oncotype DX (ODX) is expensive and of poor value to patients, physicians, and health care providers. The 3 Magee equations, Gage Algorithm, and University of Tennessee predictive algorithm all use standard clinicopathologic data to provide surrogate ODX scores. In this hypothesis-generating study, we evaluated whether these prognostic scores could be used to identify patients unlikely to benefit from additional ODX testing. PATIENTS AND METHODS: Retrospective data was collected from 302 patients with invasive ductal breast cancer and available ODX scores. Additional data was available for: Magee equations 1 (212 patients), 2 (299 patients), 3 (212 patients), Gage Algorithm (299 patients), and University of Tennessee predictive algorithm (286 patients). ODX scores were banded according to the TAILORx results. RESULTS: Correlation with ODX scores was between 0.7 and 0.8 (Gage), 0.8 and 0.9 (Magee 2, University of Tennessee predictive algorithm), and > 0.9 (Magee 1 and 3). Magee 3 was the most robust and is proposed as a screening tool: for patients aged ≤ 50 years, ODX testing would be not required if the Magee 3 score was < 14 or ≥ 20; for those aged > 50 years, ODX would not be required if the Magee 3 score was < 18 or ≥ 26. Using these cut-offs, 110 (51.9%) of 212 patients would be deemed as not requiring ODX testing, and 109 (99.1%) of110 patients would be appropriately managed. CONCLUSIONS: Use of all formulae, and the Magee 3 equation in particular, are proposed as possible screening tools for ODX testing, resulting in significantly reduced frequency of ODX testing. This requires validation in other populations.

Complex rearrangement of chromosomes 19, 21, and 22 in Ewing sarcoma involving a novel reciprocal inversion-insertion mechanism of EWS-ERG fusion gene formation: a case analysis and literature review.

EWS-ERG Ewing sarcoma (ES) gene fusions often result from complex chromosomal rearrangements. We report an unusually aggressive case of ES with an EWS-ERG fusion gene that appeared to be a result of a simple balanced and reciprocal translocation, t(19;22)(q13.2;q12.2). Subsequent molecular investigation of the primary tumor, the metastasis, and a cell line generated from this ES permitted reconstruction of each genomic step in the evolution of this complex EWS-ERG fusion. We elucidated a new mechanism of reciprocal insertion inversion between chromosome 21 and 22, involving cryptic alterations to both the ERG and EWS genes. Molecular cytogenetic investigation, using systematic analysis with locus-specific probes, identified the cognate genomic breakpoints within chromosome 21 and 22, mandatory for the excision and exchange of both 3'ERG and 3'EWS, resulting in the formation of the EWS-ERG fusion gene present on the der(22). Array comparative genomic hybridization and fluorescence in situ hybridization studies of the ES cell line derived from this tumor identified additional acquired chromosomal and genomic abnormalities, likely associated with establishment and adaptation to in vitro growth. Notably, the cell line had lost one copy of the RB1 gene within the 13q13.1 approximately q14.2 region, and also had a near-tetraploid karyotype. The significance of these findings and their relationship to other reports of variant and complex ES translocations involving the ERG gene are reviewed.

Predicting OncoDX recurrence scores with immunohistochemical markers: effect of stromelysin.

Recent reports suggest that immunohistochemistry (IHC) markers can be used to give prognostic information in breast cancer that is similar to that contained in the Genomic Health Inc. OncoDX recurrence score (Onco-RS). Our own previous work confirmed that an IHC model based on estrogen receptor (ER), progesterone receptor (PR), and Ki67 predicts 62% of the Onco-RS variability. Other markers used in the Onco-RS include proteins thought to increase tumoral invasive potential, and one such marker is matrix metalloproteinase-11, also called stromelysin 3 (ST3). The goal of this study is to examine the additional value of including ST3 in an IHC-based model that also includes ER, PR, and Ki67 in predicting the Onco-RS, as compared with an IHC model based only on ER, PR, and Ki67 (IHC-RS). The patient population consists of a retrospectively identified cohort of 91 women with ER-positive, HER2neu-negative breast cancer who completed OncoDX testing. Using stepwise multiple regression incorporating Ki67 percentage and semiquantitative ER, PR, and ST3 scores, the ST3 score was not statistically significant.

Atypical presentation of sinonasal cellular schwannoma: a nonsolitary mass with osseous, orbital, and intracranial invasion.

Objective Sinonasal cellular schwannoma represents < 4% of head and neck schwannomas. These benign tumors are typically confined to the nasal cavity or ethmoid sinus. We describe an atypical case of sinonasal cellular schwannoma with diffuse paranasal sinus involvement and both intraorbital and intracranial extension. Results A 62-year-old woman presented with a 6-month history of right orbital proptosis and right-sided headache. Subsequent imaging revealed an invasive paranasal sinus mass extending through the skull base and displacing the right orbit. Preoperative biopsies were not diagnostic but revealed a spindle cell lesion suspicious for malignancy based on lack of encapsulation, infiltration of the sinonasal submucosa, and osseous invasion. The patient underwent open skull base surgery, and pathology confirmed a S100-positive nonencapsulated cellular schwannoma. Conclusion An atypical case of sinonasal cellular schwannoma with intracranial extension is reported. Its presentation is contrary to the common view that these are isolated solitary lesions of the nasoethmoid region. We suggest that sinonasal cellular schwannoma be considered in the differential diagnosis of a poorly defined invasive paranasal sinus mass, particularly following biopsy.

Malignant peripheral nerve sheath tumor arising in a traumatic neuroma: a case report.

A 67-year-old woman with a history of breast cancer presented with a soft tissue mass at the site of a remote, non-neoplastic lumbar surgery. Excisional biopsy revealed a traumatic neuroma. Five years later she re-presented with a rapidly growing, tender nodule at the same site. An excisional biopsy was again performed and revealed a tumor composed of malignant epithelioid and spindle cells merging imperceptibly with residual traumatic neuroma. The malignant cells were positive for vimentin, S-100 and micropthalmia transcription factor. They were negative for cytokeratins, muscle markers, Melan-A, HMB45, glial fibrillary acidic protein, and myelin basic protein. Electron microscopy showed no melanosomes. The diagnosis of malignant peripheral nerve sheath tumor arising within a long-standing traumatic neuroma was rendered and represents a hitherto unreported origin of this rare, aggressive soft tissue sarcoma.

Predicting OncoDx recurrence scores with immunohistochemical markers.

Recent reports suggest that immunohistochemistry (IHC) markers can be used to give prognostic information in breast cancer that is similar to that contained in the Genomic Health Inc. OncoDx recurrence score (Onco-RS). The goal of this study is to examine the potential prognostic value of a score derived from results of a simple set of IHC tests in the prediction of the Onco-RS. A score (IHC-RS) was derived to predict the Onco-RS using IHC-based quantitative and semiquantitative results from a subset of markers selected from those used in the generation of an Onco-RS score. The patient population consists of a retrospectively identified cohort of 158 women with ER-positive, HER2neu-negative breast cancer who completed OncoDx testing. A predictive model was developed to generate the IHC-RS using stepwise multiple regression incorporating Ki67 percentage and semiquantitative ER and PR scores. Using only these 3 IHC markers, the IHC-RS predicted 62% of the Onco-RS variability (adjusted R=0.624, P=0.004). In addition, analysis of outliers in the correlation between the IHC-RS and the Onco-RS reveals the possibility of sampling error as a drawback of the Onco-RS. This is contrasted against potential interlab and intralab variability and preanalytic issues that may negatively impact the implementation of an IHC-RS.